Instrument panel speaker unit



Jan. 9, 1940. B. A. scHwARz El AL INSTRUMENT PANEL SPEAKER UNIT FiledMay '7. 1957 awe/1M ad's/mm Yak 15mm w 91/1/2121! (3X76 W00 PatentedJan. 9, 1940 UNrrEn STATES PATENT OFFlCE INSTRUMENT PANEL SPEAKER UNITware Application May 7, 1937, Serial No. 141,237

6 Claims. (01. 181-31) This invention pertains to apparatus forreproducing sound from electric currents and more particularly to loudspeaker design relating to automotive construction.

" Loud speakers mounted upon vehicle chassis have been applied to anumber of different positions in an attempt to find a satisfactoryposition in which the sound waves would travel to the occupants of themotor car with the least dis- 105 tortion and interference. The mostsatisfactory location for such speakers has been behind the instrumentpanel and they have been secured either to the rear face of theinstrument panel or to the forward face of the dash. However in 151 thedifferent cars to which any commercial set might be applied, thedistances between the instrument panel and dash vary and also theacoustic chambers caused by the differing apparatus carried by anyparticular motor car would 20 also cause different resonance chambersand interference with the propagated wave.

It is therefore an object of our invention to provide a loud speakerassembly having an acoustic chamber of definite proportion sur- 5rounding the loud speaker to control the back Wave from the speaker.

It is a further object of our invention to provide an acoustic bafllesurrounding the rear face of the loud speaker to prevent interferencebe- 9 tween the waves emanating from the two faces of the speaker.

It is a further object of our invention to provide a satisfactorycontrol housing around the back face of the speaker'mounted on theinstru- 35 ment panel to eliminate interference of the sound waves withvarious cavities formed on the dash or floor boards.

It is a still further object of our invention to provide an assembly andmounting for a loud 4:0 speaker unit so that the whole may easily beapplied to the rear face of the instrument panel.

With these and other objects in view, the embodiments of our inventionare described in the following specification and claims and illustrated45 in the accompanying drawing, in which:

' Figure l is a vertical section showing the device of our inventionmounted upon the instrument panel of a car.

Figure 2 is a sectional view taken on line 2-2 50 of Figure 1.

Figure 3 is a front elevation of the assembly in place in the instrumentpaneL In the presentcars such as that designated generally at 2, thereis provided in the front 55 portion a windshield 4 and from thewindshield the front portion of the body slopes downwardly as at 6 andprovides a vertical section in the forward portion of the drivingcompartment as shown at 8 which is conventionally termed the instrumentpanel. In the central portion of this 5 instrument panel there isprovided a series of louvers l0 and directly below the louvers there isprovided a series of circular openings designated generally at l2 inwhich there are adapted to be secured the various indicating and controlapparatus for a radio set such as indicated by knobs l4 and anindicating dial IS.

The invention of our device is adapted to be supported directly behindthis center panel as shown roughly in dotted outline in Figure 3 andcomprises a roughly rectangular frame member 18 to which is adapted tobe secured a rim 20 supporting the edge of a diaphragm 22 of a loudspeaker, the actuating unit 24 of which is supported from the rim bysuitable strap 20 means 26.

Also attached adjacent the rim 20 on the same frame and by suitablespacer means 28 is an elongated hollow housing 30 which may be ofsubstantially parabolic shape as shown, which is. of course, merelyillustrative and any other desired form may be used and which is formedof. any suitable sound deadening material such as felt or cardboardcovered with felt. To the rear portion of the speaker actuating unit issecured a plate 32 of corrugated paper, the edge portions of which touchthe inside of the elongated memher 30 to assist in supporting the battleunit. The forward edge of the rectangular frame member i8 is coveredwith a sponge rubber member 34 so 5 that when the member is drawntightly against the inner face of the instrument panel there will be nometal contact to cause rattling.

On the lower portion of the frame l8 there is secured thereto aconventional remote control unit 36 having mounted therein the controlknobs l4 and the dial l6. This unit is adapted to be clamped directlyagainst the rear face of the instrument panel and the control shaftsshould project through the openings provided therein, said controlshafts having therearound an exteriorly threaded housing with suitablesecuring nuts 38 which housing of course also projects through the faceof the panel and by tightening up the nuts 38 adjacent each of thecontrol knobs the control box 36 is rigidly secured against theinstrument panel. The dial l6 also projects through a suitable openingto be visible.

The two ends of the control box 36 are rigidly secured to the frame l8by suitable spacing sleeves ment panel and suitable tightening meansthere-' on which draw the frame 18 up tightly against the rear face ofthe panel adjacent the louvers.

In the rear portion of the member there is provided a vent Ell, thedesign of which will alter the damping characteristics of the enclosingchamber. It is therefore obvious that all of the sound emanated by the,forward portion of the speaker 22 will go through the frame l8 and outthrough the louvers and into the car while substantially all of thewaves emanated by the rear.

face will be damped in the acoustic chamber in the rear and willtherefore not cause anyinterference with the forwardly projected wavesnor will there be any interfering backwave from the dash or floor boardssuch as .52 and the pressure on the rear face of the diaphragm willremain substantially constant.

We claim:

s 1. In a sound reproducing device, a panel, a hollow frame securedthereto, a speaker unit secured to the frame, and a hollow parabolicmember formed of sound deadening material secured to the frame enclosingthe speaker unit having an opening at the end opposite to the securedend, said parabolic member serving as a'bafile to damp the vibrationsfrom the rear face of the speaker.

2. In a sound reproducing device, a panel provided with louvers, meansfor mounting a sound propagating device on the panel adjacent thelouvers, a hollow parabolic member formed of sound deadening materialand means for mounting said member to the panel to enclose the soundpropagating device to damp the waves emanating from one face of thedevice.

3. In a sound reproducing device, a panel having louvers therein, meansfor securing a hollow frame to the panel adjacent the louvers, soundinsulating material between the frame and the panel, a. soundpropagating device supported on the frame, a hollow parabolic memberformed of sound deadening material supported on the frame enclosingthesound propagating device to dam the waves from one face thereof and actas a baffie.

l. In a device of theclass described, an instrument panel having aplurality of openings therein, a control unit having portions adapted toproject through said openings for assembly and support, a framecarriedby the unit and held in juxtaposition to the panel, insulatingmeans between the frame and panel and a sound propagating device carriedby the frame to project sound through the panel.

5. In a device of the class described, an instrument panel having aplurality of openings therein, a control unit having portions adapted toproject through said. openings for assembly and support, a frame carriedby the unit and held in juxtaposition to the panel, insulating meansbetween the frame and panel, a sound propagating device carried by theframe to project sound through the panel and bafliemeans surrounding therear face of the sound propagating device.

6. In a device of the class described, an instrument panel having aplurality of openings there'- in, a control unit having portions adaptedto project through said openings for assembly and support, a framecarried by the unit and held in juxtaposition to the panel, insulatingmeans be tween the frame and panel, a sound propagating device carriedby the frame to project sound through the panel and baffle meanssurrounding the rear face of the sound propagating device, said bafflemeans comprising an elongated parabolic nonresonant membersecured to theframe having an opening in its remote end.

BERTRAM A. SCHWARZ. WILLIAM 0. DE R00.

